Collisional Dynamics of Half-Quantum Vortices in a Spinor Bose-Einstein Condensate

We present an experimental study on the interaction and dynamics of half-quantum vortices (HQVs) in an antiferromagnetic spinor Bose-Einstein condensate. By exploiting the orbit motion of a vortex dipole in a trapped condensate, we perform a collision experiment of two HQV pairs, and observe that the scattering motions of the HQVs is consistent with the short-range vortex interaction that arises from nonsingular magnetized vortex cores. We also investigate the relaxation dynamics of turbulent condensates containing many HQVs, and demonstrate that spin wave excitations are generated by the collisional motions of the HQVs. The short-range vortex interaction and the HQV-magnon coupling represent two characteristics of the HQV dynamics in the spinor superfluid.Comment: 7 pages, 6 figure

Bitcoin Double-Spending Attack Detection using Graph Neural Network

Bitcoin transactions include unspent transaction outputs (UTXOs) as their inputs and generate one or more newly owned UTXOs at specified addresses. Each UTXO can only be used as an input in a transaction once, and using it in two or more different transactions is referred to as a double-spending attack. Ultimately, due to the characteristics of the Bitcoin protocol, double-spending is impossible. However, problems may arise when a transaction is considered final even though its finality has not been fully guaranteed in order to achieve fast payment. In this paper, we propose an approach to detecting Bitcoin double-spending attacks using a graph neural network (GNN). This model predicts whether all nodes in the network contain a given payment transaction in their own memory pool (mempool) using information only obtained from some observer nodes in the network. Our experiment shows that the proposed model can detect double-spending with an accuracy of at least 0.95 when more than about 1% of the entire nodes in the network are observer nodes.Comment: 3 pages, 1 table, Accepted as poster at IEEE ICBC 202

Observation of a Geometric Hall Effect in a Spinor Bose-Einstein Condensate with a Skyrmion Spin Texture

For a spin-carrying particle moving in a spatially varying magnetic field, effective electromagnetic forces can arise due to the geometric phase associated with adiabatic spin rotation of the particle. We report the observation of a geometric Hall effect in a spinor Bose-Einstein condensate with a skyrmion spin texture. Under translational oscillations of the spin texture, the condensate resonantly develops a circular motion in a harmonic trap, demonstrating the existence of an effective Lorentz force. When the condensate circulates, quantized vortices are nucleated in the boundary region of the condensate and the vortex number increases over 100 without significant heating. We attribute the vortex nucleation to the shearing effect of the effective Lorentz force from the inhomogeneous effective magnetic field.Comment: 9 pages, 11 figure

FEASIBILITY OF BREWING MAKGEOLLI (TURBID RICE WINE) USING PARTIALLY GELATINIZED WHEAT FLOUR AND TAPIOCA FLOUR

Makgeolli is made from cooked rice or wheat, then brewed with nuruk (Korean fermentation starter) for several days. But, nowadays, attempts have been made to use various raw materials and process innovations to make makgeolli for particular purposes.  This study aimed to evaluate the quality of makgeolly made from partially gelatinized wheat flour and tapioca flour. Five different combination of wheat flour and tapioca flour were used to manufacture makgeolli. The results showed that different combination of partially gelatinized wheat flour and tapioca flour significantly affected the chemical and sensorial characteristics of makgeolli. Increasing proportion of wheat flour produced higher level of total acid, amino acidity, reducing sugar and total solid of makgeolli. Inversely, alcohol content was higher when higher level of tapioca flour was used. In general, sensorial characteristics of makgeolli made from partially gelatinized wheat flour and tapioca flour didn’t acceptable by panelists. Thus, brewing makgeolli by using partially gelatinized wheat flour and tapioca flour isn’t acceptable in term of sensorial characteristics

In vitro activity of gemifloxacin against recent clinical isolates of bacteria in Korea.

Gemifloxacin is an enhanced-affinity fluoroquinolone with broad-spectrum antibacterial activity. In Korea, resistant bacteria are relatively more prevalent than in other industrialized countries. In this study, we studied the in vitro activities of gemifloxacin, gatifloxacin, moxifloxacin, levofloxacin, ciprofloxacin, and other commonly used antimicrobial agents against 1,689 bacterial strains isolated at four Korean university hospitals during 1999-2000. Minimum inhibitory concentrations (MICs) were determined using the agar dilution method of National Committee for Clinical Laboratory Standards. Gemifloxacin had the lowest MICs for the respiratory pathogens: 90% of Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae were inhibited by 0.06, 0.03, and 0.03 mg/L, respectively. Gemifloxacin was more active than the other fluoroquinolones against methicillin-susceptible Staphylococcus aureus, coagulase-negative staphylococci, streptococci, and Enterococcus faecalis. The MIC90s of gemifloxacin for Klebsiella oxytoca, Proteus vulgaris, and non-typhoidal Salmonella spp. were 0.25, 1.0, and 0.12 mg/L, respectively, while those for other Gram-negative bacilli were 4-64 mg/L. In conclusion, gemifloxacin was the most active among the comparative agents against Gram-positive species, including respiratory pathogens isolated in Korea

Optimasi Kadar Total Penol dan Aktivitas Antioksidan Tepung Labu Kuning Menggunakan Response Surface Methodology (RSM)

Yellow pumpkin (Cucurbita moscata) is a local plant that is yet optimally utilized. It has been reported that drying temperature and pre-treatment of metabisulfite greatly affected the total phenolic contents and antioxidant activity of pumpkin flour. Response Surface Methodology (RSM) considered to be a powerful tool to optimize process conditions in order to get a high yield of particular response. Process optimization was done based on the Box-Behnken construction that consisted of 12 factorial treatments and 5 replicates of central point treatments. Factorial treatment as an independent variable were immersion of meta-bisulfite (15-45 min), temperature of draying (75-85oC), and duration of drying (8-12 h). Based on the data acquired by Box-Behnken Design, a quadratic model can predict the response at any point. The response variables correlated well with the independent variables according to the multiple regression analysis. The R2 of the model fitted for total phenolic content and DPPH scavenging activity was 0.9171 and 0.9746, respectively. Based on the model, the optimum conditions for manufacturing of pumpkin flour were 15 min of immersion of meta-bisulfite, 83.03 oC of drying temperature, and 10.04 h of drying time. Those optimized conditions produced pumpkin flour which has predicted total phenolic content of 1.83 mg GAE/g sample and DPPH scavenging activity of 91.072%. Keywords— antioxidant, flour, RSM, pumpki